Saint John group tracks migration of monarch butterflies — one tag at a time

Point Lepreau has become a popular travel destination for monarch butterflies.  

"The butterfly really is kind of in peril even though there are a lot of them around," said Jim Wilson, who is part of the Saint John Naturalists Club.

Monarch butterflies in Eastern Canada and the United States fly thousands of kilometres in the fall to spend winter in the pine and fir forests in the mountains of central Mexico. 

The Saint John club has been taking part in a North American project called Monarch Watch. The project tags and tracks the migration routes of the butterflies, gleaning information about things that influence their survival chances, including their geographic locations.

Wilson said monarch butterfly populations have seen a 90 per cent drop over the past 20 years.

"The species is now a species at risk and the numbers have declined incredibly," he said.

• Monarch butterflies raised in captivity may not migrate to Mexico 
• Monarch butterfly sightings an encouraging sign to naturalist

The wintering monarchs used to cover many hectares of forest in Mexico. They've been declining and dropped to a low of just 0.67 hectares in 2013-14, although there has been some recovery since then. 

Wilson said there are a number of reasons why the monarch butterfly has been declining, including major die-offs during storms, cold weather, the lack of milkweed plants between Mexico and Canada because of urban sprawl, the use of herbicides and roadside cutting.

Even if butterfly generations have a successful migration back to Mexico, there are still problems waiting down south.

Illegal logging in Mexico is cooling down the forested areas of high mountains, where the millions of butterflies gather.

How the project works

Circular sticky tags, each bearing the Monarch Watch name and a seven-character code, are pressed into the wings of butterflies.

The Saint John group had about 950 tags last year and this year is hoping for 1,000 of the all-weather, lightweight tags, which don't interfere with butterfly movement.

"We'll tag any monarch we can get in order to help the project and the butterfly," Wilson said.

As the butterflies make their way back to Mexico, other volunteers along the route also tag, check tags and record data.

Why Point Lepreau?

The butterflies tend to travel to that particular area, about 50 kilometres west of Saint John, because it's by the Bay of Fundy. From there, they can easily travel to places like Grand Manan and then down the coast of Maine. 

And more people are planting milkweed, a plant used for both breeding and food. There are also more blooming plants in Point Lepreau.

"I think it's working," Wilson said. 

'A rugged butterfly'

The monarch butterfly is large in size, brightly coloured and strongly veined in the wings, which helps them for their long journey south.

"[They're] almost like little bones in the wings," Wilson said. "When you pick up a monarch butterfly for the first time you're really struck by how solid it is.

"This is a big and rugged butterfly."